Alright, I took out some time to continue to play using an RC network to smooth out the PWM signal to simulate a "steady" DC voltage.
For my application of the Bar graph display I'm really only interested in being able to control the exact number of LEDs I want turned on or off. That is, I'm not so concerned about being able to read the actual analog voltage. Of course the LM 3914 is actually reading the analog voltage and turns on/off LEDs accordingly. But I'm only concerned with being able to send a PWM signal from the Netduino such that I can deterministically control the actual number of LEDs that need to be turned on. I say this because the RC network introduces lag and so the choice of the RC components could be different for your purposes. Further, I also need to be able to turn on all 10 LEDs at 3.3v.
I found that a 2.2K resistor connected to the PWM output pin on the Netduino and a 10uF capacitor connected between the other end of the resistor and ground works best. Of course the junction of the two is fed to the LM 3914 ICs pin 5. The LM 3914 and the LEDs are running off of 5v.